curl/docs/libcurl/opts/CURLSHOPT_LOCKFUNC.md
Daniel Gustafsson 8d67c61c47 curldown: Fix email address in Copyright
The curldown conversion accidentally replaced daniel@haxx.se with
just daniel.se.  This reverts back to the proper email address in
the curldown docs as well as in a few other stray places where it
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Reviewed-by: Daniel Stenberg <daniel@haxx.se>
Closes: #12997
2024-02-28 11:28:10 +01:00

1.8 KiB

c SPDX-License-Identifier Title Section Source See-also
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLSHOPT_LOCKFUNC 3 libcurl
CURLSHOPT_UNLOCKFUNC (3)
curl_share_cleanup (3)
curl_share_init (3)
curl_share_setopt (3)

NAME

CURLSHOPT_LOCKFUNC - mutex lock callback

SYNOPSIS

#include <curl/curl.h>

void lockcb(CURL *handle, curl_lock_data data, curl_lock_access access,
            void *clientp);

CURLSHcode curl_share_setopt(CURLSH *share, CURLSHOPT_LOCKFUNC, lockcb);

DESCRIPTION

Set a mutex lock callback for the share object, to allow it to get used by multiple threads concurrently. There is a corresponding CURLSHOPT_UNLOCKFUNC(3) callback called when the mutex is again released.

The lockcb argument must be a pointer to a function matching the prototype shown above. The arguments to the callback are:

handle is the currently active easy handle in use when the share object is intended to get used.

The data argument tells what kind of data libcurl wants to lock. Make sure that the callback uses a different lock for each kind of data.

access defines what access type libcurl wants, shared or single.

clientp is the private pointer you set with CURLSHOPT_USERDATA(3). This pointer is not used by libcurl itself.

PROTOCOLS

All

EXAMPLE

extern void mutex_lock(CURL *handle, curl_lock_data data,
                       curl_lock_access access, void *clientp);

int main(void)
{
  CURLSHcode sh;
  CURLSH *share = curl_share_init();
  sh = curl_share_setopt(share, CURLSHOPT_LOCKFUNC, mutex_lock);
  if(sh)
    printf("Error: %s\n", curl_share_strerror(sh));
}

AVAILABILITY

Added in 7.10

RETURN VALUE

CURLSHE_OK (zero) means that the option was set properly, non-zero means an error occurred. See libcurl-errors(3) for the full list with descriptions.